U.S. patent application number 11/257113 was filed with the patent office on 2006-04-27 for speaker device.
Invention is credited to Teruaki Kaiya, Seiya Sato.
Application Number | 20060088180 11/257113 |
Document ID | / |
Family ID | 35431276 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060088180 |
Kind Code |
A1 |
Kaiya; Teruaki ; et
al. |
April 27, 2006 |
Speaker device
Abstract
A speaker device includes a vibration system, having a voice
coil bobbin, a diaphragm, a supporting cap and a cap, and a
magnetic circuit system. The inner peripheral edge portion of the
diaphragm is mounted on an area in the vicinity of the upper end
portion of the outer peripheral wall of the voice coil bobbin. The
projecting portion of the cap is inserted into the opening of the
supporting cap, and the supporting cap is placed under the cap.
Each of the projecting portions of the cap is fixed to each of the
correspondent recessed portions of the diaphragm, and the claw
portion of the cap is fixed to the projecting portion of the
diaphragm and the third flat portion.
Inventors: |
Kaiya; Teruaki; (Tendo-Shi,
JP) ; Sato; Seiya; (Tendo-Shi, JP) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Family ID: |
35431276 |
Appl. No.: |
11/257113 |
Filed: |
October 25, 2005 |
Current U.S.
Class: |
381/397 |
Current CPC
Class: |
H04R 7/122 20130101;
H04R 9/02 20130101; H04R 9/04 20130101 |
Class at
Publication: |
381/397 |
International
Class: |
H04R 1/00 20060101
H04R001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 24, 2004 |
JP |
2004-374313 |
Oct 25, 2004 |
JP |
2004-309329 |
Claims
1. A speaker device comprising: a voice coil bobbin; a diaphragm
which is mounted on the voice coil bobbin; and a cap which is
positioned in front of the diaphragm and at a position covering the
voice coil bobbin, wherein the diaphragm has a first fixing portion
in a vicinity of an outer peripheral portion thereof and a second
fixing portion in a vicinity of a middle portion thereof, and
wherein an outer peripheral portion of the cap is bonded to the
outer peripheral portion of the diaphragm or the first fixing
portion, and a portion of the cap opposite to the second fixing
portion is bonded to the second fixing portion.
2. The speaker device according to claim 1, wherein the first
fixing portion has a projecting portion on a side opposite to the
cap and the outer peripheral portion of the cap has a hook-shape
claw portion on a side opposite to the diaphragm, and wherein the
claw portion and the projecting portion contact to be bonded.
3. The speaker device according to claim 1, wherein the second
fixing portion has plural recessed portions on a side of the cap,
wherein plural projecting portions are formed at the portion of the
cap opposite to the second fixing portion, and wherein the plural
projecting portions are inserted into the plural correspondent
recessed portions, and the plural projecting portions and the
plural recessed portions are bonded.
4. The speaker device according to claim 1, wherein a supporting
cap is provided between the voice coil bobbin and the cap, and
wherein the supporting cap is bonded to the cap, and an outer
peripheral portion of the supporting cap is bonded between the
voice coil bobbin and the diaphragm by an adhesion component.
5. The speaker device according to claim 4, wherein the supporting
cap has a contact surface contacting the cap, and has an opening at
a substantial center of the contact surface, wherein the cap has a
projecting portion projecting at a position corresponding to the
opening and on a side opposite to the supporting cap, and wherein
the projecting portion of the cap is inserted into the opening of
the supporting cap.
6. The speaker device according to claim 1, further comprising an
edge and a frame, wherein an inner peripheral portion of the edge
is mounted onto the outer peripheral portion of the diaphragm, and
an outer peripheral portion of the edge is mounted onto the
frame.
7. The speaker device according to claim 4, wherein the supporting
cap has a ventilation portion.
8. The speaker device according to claim 7, wherein the supporting
cap has an opening at a position facing a space existing among the
supporting cap, the diaphragm and the cap.
9. The speaker device according to claim 5, wherein the supporting
cap has an opening between the contact surface and the outer
peripheral portion.
10. The speaker device according to claim 7, wherein a portion of
the supporting cap facing a space existing among the supporting
cap, the diaphragm and the cap, a part of the portion or the entire
supporting cap is formed by a material having permeability.
11. The speaker device according to claim 7, wherein the diaphragm
has an opening at a position facing a space existing among the
supporting cap, the diaphragm and the cap.
12. The speaker device according to claim 6, wherein the frame has
an opening at a position facing a space existing among the frame,
the diaphragm and the edge.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a mounting structure of a
cap and a diaphragm in a speaker device.
[0003] 2. Description of Related Art
[0004] Conventionally, there is known an external-magnet type
speaker device including a vibration system having a voice coil
bobbin, a diaphragm and a cap having a dustproof function, and a
magnetic circuit system having a yokes a magnet and a plate. In
such a speaker device, one portion (mounting surface), of an outer
peripheral edge portion of the cap is mounted on an area in the
vicinity of an outer peripheral edge portion of the diaphragm via
an adhesive, and the cap is arranged at a position covering an
upper surface of the voice coil bobbin, for example.
[0005] There is known a speaker device in which the outer
peripheral edge portion of the diaphragm having an upper-side
diaphragm and a lower-side diaphragm is mounted onto an inner side
edge (see U.S. Pat. No. 6,496,590 and No. 6,501,844, for example).
In addition, there is known the speaker device in which the outer
peripheral edge portion of a dustproof cap is mounted onto the side
of the outer peripheral edge portion of the diaphragm via an
adhesive tape (see U.S. Pat. No. 6,639,993, for example). Moreover,
there is known the speaker device in which an opening is formed on
a pole piece (see U.S. Pat. No. 5,734,734, for example).
[0006] However, in the above-mentioned speaker device, a mounting
surface (attachment surface) of the cap to the diaphragm is
positioned on the side of the outer peripheral edge portion of the
cap, and an adhesion area of the cap and the diaphragm is small.
Therefore, a vibrating area of the cap at the time of driving of
the speaker device is large, and due to the vibration, an abnormal
sound (flutter) problematically occurs from the cap. As a method of
avoiding such a problem, there is known a method of making the cap
thicker so that the vibration of the cap hardly occurs, thereby
preventing the occurrence of the abnormal sound (flutter) However,
if such a method is employed, the cap becomes heavy by the amount
of increased thickness of the cap, and sensitivity of the speaker
device decreases as a new problem
SUMMARY OF THE INVENTION
[0007] The present invention has been achieved in order to solve
the above problems. It is an object of this invention to provide a
speaker device, having a mounting structure of a cap and a
diaphragm, capable of preventing occurrence of an abnormal sound
(flutter) of the cap.
[0008] According to one aspect of the present invention, there is
provided a speaker device including: a voice coil bobbin; a
diaphragm which is mounted on the voice coil bobbin; and a cap
which is positioned in front of the diaphragm and at a position
covering the voice coil bobbin, wherein the diaphragm has a first
fixing portion in a vicinity of an outer peripheral portion thereof
and a second fixing portion in a vicinity of a middle portion
thereof, and wherein an outer peripheral portion of the cap is
bonded to the outer peripheral portion of the diaphragm or the
first fixing portion, and a portion of the cap opposite to the
second fixing portion is bonded to the second fixing portion.
[0009] The above speaker device includes the voice coil bobbin, the
diaphragm formed into a cone shape, mounted onto the voice coil
bobbin, and the cap positioned in front of the diaphragm, i.e., on
a sound output side, and at the position covering the voice coil
bobbin and having a dustproof function, for example.
[0010] The speaker device includes the first fixing portion in the
vicinity of the outer peripheral portion of the diaphragm, and the
second fixing portion in the vicinity of the middle portion of the
diaphragm. The outer peripheral portion of the cap is bonded
(fixed) to the outer peripheral portion of the diaphragm or the
first fixing portion via an adhesion component for example. In
addition, the portion of the cap opposite to the second fixing
portion is bonded to the second fixing portion via the adhesion
component, for example. Namely, the cap is bonded to the diaphragm
in a manner divided into the inner side portion and the outer side
portion of the second fixing portion, with the substantial middle
portion as a border thereof.
[0011] Therefore, when the voice coil bobbin is driven in the axis
direction of the speaker device, the diaphragm and the cap
accordingly vibrate in the axis direction, too. A vibrating area of
the cap is an inner side portion of the second fixing portion, so
the outer side portion of the second fixing portion hardly
vibrates. This is mainly because supporting strength of the
diaphragm is larger at the outer side portion of the second fixing
portion than the inner side portion of the second fixing portion
and the outer side portion of the second fixing portion is hard to
vibrate. Thus, in the speaker device, at the time of driving, the
vibrating area of the cap is small, and the occurrence of the
abnormal sound (flutter) from the cap can be prevented.
Additionally, as described above, since the cap and the diaphragm
are bonded at two positions, i.e., at the first fixing portion and
the second fixing portion, a bonding area therebetween increases in
comparison with the case that the cap and the diaphragm are fixed
only at the outer peripheral edge portions thereof. Thus, the
occurrence of the abnormal sound can be prevented without making
the diaphragm and the cap thicker, and the strength of the
diaphragm and the bonding strength between the diaphragm and the
cap can be improved Hence, the diaphragm and the cap can be
lighter, and sensitivity of the speaker device can be improved.
[0012] In a preferred example, the first fixing portion may have a
projecting portion on a side opposite to the cap, and the outer
peripheral portion of the cap may have a hook-shape claw portion on
a side opposite to the diaphragm; and the claw portion and the
projecting portion may contact to be bonded. In addition, the
second fixing portion may have plural recessed portions on a side
of the cap; plural projecting portions may be formed at the portion
of the cap opposite to the second fixing portion; and the plural
projecting portions may be inserted into the plural correspondent
recessed portions, and the plural projecting portions and the
plural recessed portions may be bonded. Moreover, in a preferred
example, the speaker device may further include an edge and a
frame, wherein an inner peripheral portion of the edge is mounted
onto the outer peripheral portion of the diaphragm, and an outer
peripheral portion of the edge is mounted onto the frame.
[0013] In another form of the above speaker device, a supporting
cap may be provided between the voice coil bobbin and the cap; and
the supporting cap may be bonded to the cap, and an outer
peripheral portion of the supporting cap may be bonded between the
voice coil bobbin and the diaphragm by an adhesion component.
[0014] In accordance with the form, the supporting cap formed into
the cup shape is provided between the voice coil bobbin and the
cap, for example. The supporting cap is bonded to the cap. The
outer peripheral portion of the supporting cap is bonded between
the voice coil bobbin and the diaphragm by the adhesion component.
Thereby, the bonding strength between the cap and the diaphragm can
be further improved.
[0015] In a preferred example, the supporting cap may have a
contact surface contacting the cap, and may have an opening at a
substantial center of the contact surface; the cap may have a
projecting portion projecting at a position corresponding to the
opening and on a side opposite to the supporting cap; and the
projecting portion of the cap may be inserted into the opening of
the supporting cap. Thereby, the supporting cap can be mounted onto
an appropriate position of the cap.
[0016] In another form of the above speaker device, the supporting
cap may have a ventilation portion.
[0017] In the speaker device including the supporting cap having no
ventilation portion, as the voice coil bobbin moves to the side
opposite to the sound output side, the space existing among the
supporting cap, the voice coil bobbin and the magnetic circuit is
compressed, and the pressure in the space becomes high. Thereby,
the voice coil bobbin becomes hard to move in the direction. That
is, a mechanical resistance at the time of the movement of the
voice coil bobbin increases.
[0018] As for this point, in the above speaker device, since the
supporting cap has the ventilation portion, even when the voice
coil bobbin moves to the side opposite to the sound output side,
the space is not compressed, and the pressure in the space does not
become high. Therefore, the voice coil bobbin can easily move to
the side opposite to the sound output side, and the mechanical
resistance at the time of the movement of the voice coil bobbin can
be decreased. Thereby, a deterioration of sound quality can be
prevented.
[0019] In a preferred example, the supporting cap may have an
opening as a ventilation portion at a position facing a space
existing among the supporting cap, the diaphragm and the cap. In
addition, the supporting cap may have an opening as a ventilation
portion between the contact surface and the outer peripheral
portion.
[0020] In addition, in the speaker device including the supporting
cap having no ventilation portion, as the voice coil bobbin moves
to the side opposite to the sound output side, the pressure in the
space existing among the supporting cap, the voice coil bobbin and
the magnetic circuit becomes high. Thus, the strength (bonding
strength) of the components of the vibration system in the speaker
device has to be reinforced. In this point, in the above speaker
device, since the permeability is ensured, the pressure in the
space does not become high. Therefore, the strength (bonding
strength) of the components of the vibration system does not have
to be reinforced in a positive manner. Namely, since the
above-mentioned speaker device includes the ventilation portion,
the strength (bonding strength) among the respective components of
the vibration system becomes high at the time of the driving of the
speaker device, in comparison with the speaker device including no
ventilation portion. This is called "reinforcement effect".
Thereby, the vibration system can be operated with appropriate
softness. As a result, the vibration system can be appropriately
controlled, and the speaker device can be easily in a still state.
Namely, a damping effect can be improved.
[0021] In another form of the above speaker device, a portion of
the supporting cap facing a space existing among the supporting
cap, the diaphragm and the cap, a part of the portion or the entire
supporting cap may be formed by a material having permeability,
e.g., a material such as a fabric on which large meshes are formed.
Thereby, the effect similar to the case that the opening is
provided on the supporting cap as the ventilation portion can be
obtained, and the mechanical resistance at the time of the movement
of the voice coil bobbin can be decreased. Hence, the deterioration
of the sound quality can be prevented.
[0022] In another form of the above speaker device, the diaphragm
may have an opening at a position facing a space existing among the
supporting cap, the diaphragm and the cap. Thereby, the space
existing among the supporting cap, the diaphragm and the cap is
connected to the space existing among the diaphragm, the edge and
the frame via the opening. In still another form of the above
speaker device, the frame may have an opening at a position facing
a space existing among the frame, the diaphragm and the edge.
Thereby, the space existing among the frame, the diaphragm and the
edge is connected to the external space of the speaker device via
the opening. Therefore, in accordance with the form, it can be
further prevented that the pressure of the space existing among the
supporting cap, the voice coil bobbin and the magnetic circuit
becomes high, and the mechanical resistance at the time of the
movement of the voice coil bobbin can be decreased. Hence, the
deterioration of the sound quality can be further prevented.
[0023] The nature, utility, and further features of this invention
will be more clearly apparent from the following detailed
description with respect to preferred embodiment of the invention
when read in conjunction with the accompanying drawings briefly
described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 shows a cross-sectional view of a speaker device
according to a first embodiment of the present invention;
[0025] FIGS. 2A and 2B show a plan view and a cross-sectional view
of a diaphragm according to the first embodiment;
[0026] FIGS. 3A and 3B show a perspective view and a
cross-sectional view of a supporting cap according to the first
embodiment;
[0027] FIGS. 4A and 4B show a plan view and a cross-sectional view
of a cap according to the first embodiment;
[0028] FIG. 5 is a partly cross-sectional view showing amounting
structure of the cap and the diaphragm according to the first
embodiment;
[0029] FIG. 6 is a partly cross-sectional view showing the mounting
structure of the cap and the diaphragm according to a comparative
example;
[0030] FIG. 7 is a partly cross-sectional view showing an example
of the mounting structure of the cap and the diaphragm according to
a modification;
[0031] FIGS. 8A and 8B show a perspective view and a
cross-sectional view of a supporting cap according to a second
embodiment of the present invention;
[0032] FIGS. 9A and 9B show a plan view and a cross-sectional view
of the diaphragm according to the second embodiment;
[0033] FIG. 10 is a partly cross-sectional view of the speaker
device explaining operation and effect of a ventilation portion of
the second embodiment; and
[0034] FIGS. 11A to 11C are perspective views of the supporting cap
in which portions corresponding to plural openings on a side wall
of the supporting cap, the entire side wall and the entire
supporting cap are constructed by a material having permeability
such as a fabric on which large meshes are formed,
respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] The preferred embodiments of the present invention will now
be described below with reference to the attached drawings
First Embodiment
[0036] In a first embodiment, it is prevented that an abnormal
sound (flutter) occurs from the cap at the time of the driving of
the speaker device, by bonding the cap and the diaphragm at a
predetermined position.
(Configuration of Speaker Device)
[0037] FIG. 1 schematically shows a configuration of a speaker
device 100 according to the first embodiment of the present
invention. The speaker device 100 of the first embodiment is the
so-called subwoofer-type speaker device. Therefore, the speaker
device 100 of this embodiment can be preferably used as an
on-vehicle speaker. FIG. 1 shows a cross-sectional view when
cutting the speaker device 100 by a plane including a central axis
thereof. The description will be given of the configuration of the
speaker device 100 of the first embodiment with reference to FIG. 1
to FIGS. 4A and 4B, below.
[0038] As shown in FIG. 1, the speaker device 100 mainly includes a
magnetic circuit system 20 having a yoke 1, a magnet 2 and a plate
3, a vibration system 30 having a frame 4, a damper 6, a voice coil
bobbin 7, a voice coil B, a diaphragm 9, an edge 13, a supporting
cap 11 and a cap 12, and plural terminal members 5, and a mounting
member 18 as various kinds of members.
[0039] First, the description will be given of respective
components of the magnetic circuit system 20.
[0040] The magnetic circuit system 20 is configured as an
external-magnet type magnetic circuit. The yoke 1 has a cylindrical
pole portion 1a and a flange portion 1b extending in an outward
direction from an outer peripheral wall thereof. The annular magnet
2, which is formed into an annular shape, is fixed onto an upper
surface of the flange portion 1b being the component of the yoke 1.
The annular plate 3, which is formed into an annular shape, is
fixed onto the annular magnet 2. In the magnetic circuit system 20,
the magnetic circuit is constructed by the magnet 2 and the plate
3, and magnetic flux of the magnet 2 concentrates on a magnetic gap
16 formed between an inner peripheral wall of the plate 3 and an
outer peripheral wall of the pole portion 1a.
[0041] Next, the description will be given of respective components
of the vibration system 30.
[0042] The various components of the speaker device 100 are fixed
onto the frame 4, and the frame 4 serves as supporting member of
the components. The frame 4 has a first flat portion 4a, a second
flat portion 4b and a third flat portion 4c, whose upper surfaces
ensure flatness. The first flat portion 4a is formed at a position
on the lower side of the frame 4. The lower surface of the first
flat portion 4a is fixed onto the annular magnet 3. The second flat
portion 4b is formed at a substantial middle position of the frame
4. Onto an upper surface of the second flat portion 4b, the outer
peripheral edge portion of the damper 6 is fixed. The third flat
portion 4c is formed at a position on an upper side of the frame 4.
Onto an upper surface of the third flat portion 4c, an outer
peripheral edge portion of the mounting member 18, which will be
described later, is mounted.
[0043] The voice coil bobbin 7 is formed into a substantially
cylindrical shape. The voice coil 8, which will be described later,
is wound around the vicinity of the lower end portion of the outer
peripheral wall of the voice coil bobbin 7. The vicinity of the
lower end portion of the outer peripheral wall of the voice coil
bobbin 7 is opposite to each of the inner peripheral walls of the
annular magnet 2 and plate 3 with a constant space therebetween. On
the other hand, the vicinity of the lower end portion of the inner
peripheral wall of the voice coil bobbin 7 is opposite to the outer
peripheral wall of the pole portion 1a being a component of the
yoke 1 with a constant space. A gap (magnetic gap 16) is formed
between the outer peripheral wall of the pole portion 1a and the
inner peripheral wall of the plate 3.
[0044] The voice coil 8 has a pair of positive/negative lead wires
(not shown). A lead wire at the positive side is an input wiring
for an L (or R) channel signal, and a lead wire at the negative
side is an input wiring for a ground (GND: ground) signal. Each of
the lead wires is electrically connected to one end side of each
terminal member 5 positioned on a second flat portion 4b of the
frame 4 via each of tinsel cords (not shown). On the other hand,
the other end side of each terminal member 5 is electrically
connected to each input wiring of the amplifier. Therefore, the
electric signal of one channel is inputted to the voice coil 8 from
the amplifier via each of terminal members 5, each of the tinsel
cords (not shown) and each of the lead wires.
[0045] The damper 6 is formed into an annular shape, and has an
elastic portion formed with concentric corrugations, The outer
peripheral edge portion of the damper 6 is fixed onto the second
flat portion 4b of the frame 4, and the inner peripheral edge
portion of the damper 6 is fixed to the outer peripheral wall of
the voice coil bobbin 7.
[0046] Various kinds of materials such as paper, high polymer and
metal can be applied to the diaphragm 9 in accordance with the
various use purposes. FIGS. 2A and 2B show a configuration of the
diaphragm 9. FIG. 2A shows a plan view of the diaphragm 9 observed
from the direction opposite to an arrow Y1 shown in FIG. 1 (i.e., a
backside plan view of the diaphragm 9 observed from the lower side
of FIG. 1). FIG. 2B shows a cross-sectional view of the diaphragm 9
taken along a cut line A-A' including a central point O in FIG. 2A.
As shown in FIGS. 2A and 2B, the diaphragm 9 formed into a
so-called cone shape has a first flat portion 9a, a second flat
portion 9b and a third flat portion 9c, whose upper surfaces ensure
flatness. The first flat portion 9a is formed at a substantially
middle position of the upper surface (front side) of the diaphragm
9. On the first flat portion 9a, plural recessed portions 9ab
formed into a shape similar to an arch-shape are formed along the
direction of the circumference with an appropriate space. The
second flat portion 9b is formed in the vicinity of the outer
peripheral edge portion of the upper surface of the diaphragm 9,
i.e., at a position in the vicinity of the third flat portion 9c.
On the second flat portion 9b, a projecting portion 9ba is formed
along the direction of the circumference. The third flat portion 9c
is formed at the outer peripheral edge portion of the upper surface
of the diaphragm 9. Onto the third flat portion 9c, the inner
peripheral edge portion of the mounting member 18 formed into the
substantially annular shape is mounted. The mounting member 18
functions to stably mount the diaphragm 9 onto the frame 4. On the
upper surface of the inner peripheral edge portion of the mounting
member 18, the inner peripheral edge portion of the edge 13, formed
into a substantially half round shape when cross-sectionally
observed, is mounted. On the other hand, in the vicinity of the
outer peripheral edge portion of the mounting member 18, the outer
peripheral edge portion of the edge 13 is mounted. As shown in FIG.
1, the inner peripheral edge portion of the diaphragm 9 is mounted
onto an area in the vicinity of the upper end portion of the outer
peripheral wall of the voice coil bobbin 7 via an adhesive 10. In
addition, the inner peripheral edge portion of the diaphragm 9 is
also fixed to the inner peripheral edge portion of the damper 6 via
the adhesive 10. As shown in FIG. 1, the lower surface of the outer
peripheral edge portion of the mounting member 18 is fixed onto the
third flat portion 4c of the frame 4.
[0047] A supporting cap 11 is mounted on the side of the lower
surface of a cap 12 and at a position covering the upper surface of
the voice coil bobbin 7. FIGS. 3A and 3B show a configuration of
the supporting cap 11. FIG. 3A shows a perspective view of the
supporting cap 11. FIG. 3B shows a cross-sectional view when
cutting the supporting cap 11 shown in FIG. 3A by a plane including
a central axis thereof. As shown in FIGS. 3A and 3B, the supporting
cap 11 is formed into a substantially cup shape, and has an upper
surface 11a and an outer peripheral edge portion 11b. At the
substantial center of the upper surface 11a, an opening 11ab is
formed. As shown in FIG. 1, a projecting portion 12a of the cap 12,
which will be described later, is inserted into the opening 11ab of
the supporting cap 11 having such a configuration, and the
supporting cap 11 is mounted on the side of the lower surface of
the cap 12. In addition, the supporting cap 11 is arranged at the
position covering the upper surface of the voice coil bobbin 7, and
the outer peripheral edge portion of the supporting cap 11 is fixed
to a position in the vicinity of the upper end portion of the outer
peripheral wall of the voice coil bobbin 7 via the adhesive 10.
[0048] The cap 12 is mounted on the diaphragm 9 so as to cover the
upper surface of the diaphragm 9. Thereby, the cap 12 has a
function of preventing dust and a foreign material from entering
the speaker device 100. FIGS. 4A and 4B show a configuration of the
cap 12. FIG. 4A shows a plan view of the cap 11 observed from the
direction opposite to the arrow Y1 shown in FIG. 1 (i.e., a
backside plan view of the cap 12 observed from the lower portion of
FIG. 1). FIG. 4B shows a cross-sectional view of the cap 11 taken
along a cut line B-B' including the central point O shown in FIG.
4A. As shown in FIGS. 4A and 4B, the cap 12 is formed into a
substantially disc-type plan shape, and has the projecting portion
12a, plural recessed portion 12b, plural projecting portions (ribs)
12c and a claw portion 12d. The projecting portion 12a projects
from the substantially central position on the lower surface of the
cap 12. The projecting portion 12a is inserted into the opening
11ab of the supporting cap 11. Thereby, the projecting portion 12a
has a function of positioning the supporting cap 11 at the
appropriate position of the cap 12. The plural recessed portions
12b are formed along the circumferential direction in the vicinity
of the outer peripheral edge portion of the upper surface of the
cap 12 and with an appropriate space. Each of the projecting
portions 12c is formed into the substantially arch-shape, and
projects from the lower surface of each of the correspondent
recessed portions 12b. The claw portion 12d is formed into a hook
shape, and is formed at the outer peripheral edge portion of the
lower surface of the cap 12 and along the circumferential
direction. It is noted that the mounting structure of the cap 12
onto the diaphragm 9 will be described later.
[0049] In the above-mentioned speaker device 100, the electric
signal outputted from the amplifier is outputted to the voice coil
8 via each of the terminal members 5, each of the tinsel cords (not
shown) and each of the lead wires. Thereby, driving force occurs to
the voice coil 8 in the magnetic gap 16, and vibrates the diaphragm
9 in the axis direction of the speaker device 100. In this way, the
speaker device 100 emits acoustic waves in the direction of the
arrow Y1.
(Mounting Structure of Cap and Diaphragm)
[0050] Next, the description will be given of the mounting
structure of the cap and the diaphragm, which is the characteristic
of the present invention, with reference to FIG. 5. FIG. 5 is a
cross-sectional view in which a broken line area E10 shown in FIG.
1 is enlarged, and it particularly illustrates the mounting
structure of the cap 12 and the diaphragm 9. It is noted that the
description will be mainly given of components being the
characteristic of the present invention below.
[0051] The inner peripheral edge portion of the diaphragm 9 is
mounted onto a position in the vicinity of the upper end portion of
the outer peripheral wall of the voice coil bobbin 7 via the
adhesive 10. The projecting portion 12a of the cap 12 is inserted
into the opening 11ab of the supporting cap 11, and the upper
surface 11a of the supporting cap 11 contacts the correspondent
lower surface of the cap 12. Thereby, the supporting cap 11 is
mounted onto the appropriate position of the cap 12.
[0052] The inner peripheral wall of the claw portion 12d of the cap
12 contacts the outer peripheral wall of the projecting portion 9ba
of the diaphragm 9, and the claw portion 12d is fixed to the
projecting portion 9ba and the third flat portion 9c (hereinafter
also referred to as "first fixing portion") via an adhesive (not
shown). Each projecting portion 12c of the cap 12 is inserted into
each correspondent recessed portion 9ab of the diaphragm 9 to be
fixed into the recessed portion 9ab (hereinafter also referred to
as "second fixing portion") via the adhesive 10. In this manner,
the cap 12 is mounted on the diaphragm 9. The outer peripheral edge
portion 11b of the supporting cap 11 is arranged at the position in
the vicinity of the upper end of the voice coil bobbin 7 to be
fixed thereto via the adhesive 1 (hereinafter also referred to as
"third fixing portion").
[0053] Next, the description will be given of characteristic
operation and effect of the present invention in comparison with a
comparative example. FIG. 6 shows a partly perspective view of a
speaker device according to the comparative example. The same
reference numerals are given to the same components as the
components of the present invention below, and an explanation
thereof will be simplified.
[0054] First, the description will be given of the main components
of the speaker device according to the comparative example. As
shown in FIG. 6, the inner peripheral edge portion of the damper 6
is mounted on the outer peripheral wall of the voice coil bobbin 7
via the adhesive 10, and the outer peripheral edge portion of the
damper 6 is mounted on the second flat portion 4b of the frame 4.
The inner peripheral edge portion of the diaphragm 9 is mounted
onto the area in the vicinity of the upper end portion on the outer
peripheral wall of the voice coil bobbin 7 via the adhesive 10. The
inner peripheral edge portion of the diaphragm 9 and the inner
peripheral edge portion of the damper 6 are attached to each other
by the adhesive 10. A cap 20 is formed into a substantial disc-type
plan shape, and has the substantially same size (area) as the size
of the cap 12 of the present invention. The outer peripheral edge
portion of the cap 20 is mounted on the area in the vicinity of the
outer peripheral edge portion (an area corresponding to the broken
line area E5) of the diaphragm 9 via the adhesive 10 (not shown).
The inner peripheral edge portion of the mounting member 1 is
mounted on the third flat portion 9c of the diaphragm 9, and the
outer peripheral edge portion of the mounting member 18 is mounted
onto the third flat portion 4c of the frame 4. The inner peripheral
edge portion of the edge 13 is mounted onto the inner peripheral
edge portion of the mounting member 18, and the outer peripheral
edge portion of the edge 13 is mounted onto the outer peripheral
edge portion of the mounting member 18. Therefore, the inner
peripheral edge portion of the edge 13 is opposite to the third
flat portion 9c of the diaphragm 9 via the mounting member 18, and
the outer peripheral edge portion of the edge 13 is opposite to the
third flat portion 4c of the frame 4 via the mounting member
18.
[0055] Next, the description will be given of the characteristic
operation and effect of the present invention in comparison with
the comparative example, with reference to FIG. 1, FIG. 5 and FIG.
6.
[0056] In the comparative example, the cap 20 is fixed to the one
portion of the diaphragm 9 corresponding to the broken line area E5
via the adhesive (not shown). When the voice coil bobbin 7 is
driven in the direction of an arrow Y2, the cap 20 accordingly
vibrates in the direction of an arrow Y3, too. At this time, the
area in which the cap 20 vibrates becomes an area E2 other than the
attached area. The area E2 substantially corresponds to the area of
the portion of the cap 20 having a diameter D2. Like this, in the
comparative example, since the adhesion area of the cap 20 and the
diaphragm 9 is small and the vibrating area E2 is large compared
with the whole area of the cap 20 (corresponding to the total area
of the cap 20), the abnormal sound (flutter) occurs from the cap 20
due to the vibration In addition, since the adhesion area of the
cap 20 and the diaphragm 9 is small, the bonding strength
therebetween is also small.
[0057] On the contrary, in the present invention, as shown in FIG.
1 and FIG. 5, the cap 12 is fixed to the second fixing portion
corresponding to the substantially middle position of the cap 12
and the first fixing portion in the vicinity of the outer
peripheral edge portion of the cap 12 via the adhesive 10. Namely,
the cap 12 is fixed to the diaphragm 9 in a manner being divided
into two portions corresponding to the area E1 and an area E3 with
the middle position of the cap 12 serving as the border. As shown
in FIG. 1, when the voice coil bobbin 7 is driven in the direction
of the arrow Y2, the cap 12 accordingly vibrates in the direction
of the arrow Y3, too.
[0058] At this time, the area in which the cap 12 vibrates becomes
the area on the inner side of the second filling portion, i.e., the
area E1 (<E2), and the area E3 on the outer side of the second
fixing portion hardly vibrates. This is mainly because the
supporting strength of the diaphragm 9 in the area E3 on the outer
side of the second fixing portion is larger than the supporting
strength in the area E1 on the inner side of the second fixing
portion and hence the area E3 is hard to vibrate. Therefore, in the
speaker device 100, at the time of the driving thereof, since the
area in which the cap 12 vibrates is small, it can be prevented
that the abnormal sound (flutter) occurs from the cap 12. In
addition, as described above, since the cap 12 and the diaphragm 9
are bonded at the first and second fixing portions, the bonding
area therebetween increases as described above. Thus, without
making the diaphragm 9 and the cap 12 thick, the occurrence of the
abnormal sound from the cap 12 can be prevented. Moreover, the
strength of the diaphragm 9 and the bonding strength of the
diaphragm 9 and the cap 12 can be improved. Therefore, the
diaphragm 9 and the cap 12 can be lighter, and the sensitivity of
the speaker device 100 can be improved.
[0059] Additionally, in the present inventions the supporting cap
11 is further provided, and the outer peripheral edge portion
thereof is fixed to the third fixing portion. Therefore, the
bonding strength of the cap 12 and the diaphragm 9 can be further
improved.
Second Embodiment
[0060] In a second embodiment, by providing the ventilation portion
on the above-mentioned components of the speaker device 100, e.g.,
the supporting cap 11, the mechanical resistance at the time of the
movement of the vibration system 30 is reduced. Thereby, the
deterioration of the sound quality can be prevented.
[0061] First, the outline of the second embodiment will be
explained with reference to FIG. 1.
[0062] In the speaker device 100 shown in FIG. 1, a space S1 among
the diaphragm 9, the edge 13, the frame 4 and the damper 6 and a
space S2 among the diaphragm 9, the cap 12 and the supporting cap
11 are closed, respectively In addition, a space S3 among the voice
coil bobbin 7 formed into a substantially cylindrical shape, the
supporting cap 11 and the pole portion 12 is connected to a space
S4 among the magnet 2, the plate 3 and the yoke 1 via the magnetic
gap 16.
[0063] In the speaker device 100 having such a configuration, when
the voice coil bobbin 7 is assumed to move in the direction of the
arrow Y1, the supporting cap 11 accordingly moves in the direction
away from the pole portion 1a, Thus, one part of the air existing
in the space S4 flows into the space S3 via the magnetic gap 16,
and the volume of the space S3 gradually becomes large. Thereby,
the pressure in the space S3 becomes low. On the contrary, in the
speaker device 100, when the voice coil bobbin 7 is assumed to move
in the direction opposite to the arrow Y1, the supporting cap 11
accordingly moves in the direction toward the upper surface of the
pole portion 1a. Thus, the one part of the air existing in the
space S3 is discharged into the space S4 via the magnetic gap 16,
and the volume of the space s3 gradually becomes small. Namely, in
this case, the space S3 is compressed, and the pressure in the
space S3 becomes high.
[0064] As described above, in the above-mentioned speaker device
100, in accordance with the movement of the voice coil-bobbin 7 in
the direction of the arrow Y2, the volume of the space S3 becomes
large, or conversely becomes small. Particularly, when the voice
coil bobbin 7 moves in the direction opposite to the arrow Y1, the
pressure in the space S3 becomes high. Therefore, the voice coil
bobbin 7 is hard to move in the direction opposite to the arrow Y1.
Namely, in this case, the mechanical resistance at the time of the
movement of the voice coil bobbin 7 increases. Therefore, due to
the degree of the mechanical resistance at the time of the movement
of the voice coil bobbin 7, it may become difficult to
appropriately vibrate the diaphragm 9, and the sound quality may
deteriorate.
[0065] Hence, in order to avoid the occurrence of such a problem,
the mechanical resistance at the time of the movement of the voice
coil bobbin 7 has to be decreased by some sort of
countermeasure.
[0066] In order to achieve such a object, by providing the
ventilation portion on the supporting cap 11, it is realized that
the air can freely flow at least between the space S2 and the space
S3. If such a configuration is employed, in FIG. 1, when the voice
coil bobbin 7 is assumed to move in the direction opposite to the
arrow Y1, the one part of the air existing in the space S3 is
discharged to the space S4, as described above. At this time, the
one part of the air existing in the space S2 flows into the space
S3 via the ventilation portion provided on the supporting cap 11.
Therefore, in this case, in comparison with the supporting cap 11
having no ventilation portion, the pressure in the space S3 can be
low, and the voice coil bobbin 7 can easily move in the direction
opposite to the arrow Y1. Namely, in this case, the mechanical
resistance at the time of the movement of the voice coil bobbin 7
can be decreased.
[0067] Based on the above-mentioned consideration result, as a
concrete countermeasure thereof, in the second embodiment, the
ventilation portions, i.e., plural openings, are provided at
predetermined positions of the supporting cap 11. In addition, in
the second embodiment, plural openings functioning as the
ventilation portions are provided on the diaphragm 9 and the frame
4 so that the mechanical resistance at the time of the movement of
the voice coil bobbin 7 can be further decreased.
[0068] FIGS. 8A and 8B show the configuration of the supporting cap
11 having the plural openings functioning as the ventilation
portions. FIG. 8A shows a perspective view of the supporting cap 11
having the plural openings, and FIG. 8B shows a cross-sectional
view when cutting the supporting cap 11 shown in FIG. 8A by a plane
including a central axis thereof. Other than such a point that the
supporting cap 11 shown in FIGS. 8A and 8B has the plural openings,
the configuration of the supporting cap 11 shown in FIGS. 8A and 8B
is similar to the configuration of the supporting cap 11 shown in
FIGS. 3A and 3B. In addition, FIGS. 9A and 9B show the
configuration of the diaphragm 9 having the plural openings
functioning as the ventilation portions. FIG. 9A shows a plan view
of the diaphragm 9 having the plural openings, and FIG. 9B shows a
cross-sectional view taken along a cut line A-A' including a
central point O in FIG. 9A. Other than such a point that the
diaphragm 9 shown in FIGS. 9A and 9B has the plural openings, the
configuration of the diaphragm 9 shown in FIGS. 9A and 9D are same
as the configuration of the diaphragm 9 shown in FIGS. 2A and 2B.
In addition, FIG. 10 shows the frame 4 having the plural openings
functioning as the ventilation portions. FIG. 10 is a
cross-sectional view substantially corresponding to FIG. 5, and the
pole portion 1a is also shown in FIG. 10 for ease of explanation.
It is noted that the only one opening is shown for convenience of
the illustration in FIG. 10.
[0069] First, as shown in FIGS. 8A and 8B, the supporting cap 11
has a side wall 11c between the upper surface 11a and the outer
peripheral edge portion 11b. It is noted that the upper surface
11a, the outer peripheral edge portion 11b and the side wall 11c
are integrally formed. On the side wall 11c, plural openings 11ca
are formed along the circumferential direction and with the
appropriate space. The plural openings 11ca function as the
above-mentioned ventilation portions.
[0070] Next, as shown in FIGS. 9A and 98, the diaphragm 9 has a
side wall 9d between the first flat portion 9a and the inner
peripheral edge portion. On the side wall 9d, plural openings 9da
are formed along the circumferential direction and with the
appropriate space. Next, as shown in FIG. 10, the frame 4 has
plural openings 4da. The plural openings 4da are formed on a side
wall 4d positioned between the second flat portion 4b and the third
flat portion 4c. In addition, the plural openings 4da are formed
along the circumferential direction of the side wall 4d and with
the appropriate space.
[0071] FIG. 10 shows the state that the supporting cap 11, the
diaphragm 9 and the frame 4 having the above-mentioned ventilation
portions are mounted onto the speaker device 100.
[0072] In FIG. 10, the plural openings 11ca of the supporting cap
11 neighbor and face the space S2 existing among the diaphragm 9,
the side wall 11c of the supporting cap 11 and the cap 12 and the
space S3 existing among the supporting cap 11, the inner peripheral
wall of the voice coil bobbin 7 and the pole portion 1a,
respectively. The space S2 and the space S3 are connected via the
plural openings 11ca. In addition, the plural openings 9da of the
diaphragm 9 neighbor and face the space S2 and the space S1
existing among the diaphragm 9, the edge 13, the side wall 4d of
the frame 4 and the damper 6, respectively. The space S1 and the
space S2 are connected via the plural openings 9da. Moreover, the
plural openings 4da of the frame 4 neighbor and face the space S1
and the external space of the speaker device 100, respectively, and
the space S1 and the external space are connected via the plural
openings 4da. Therefore, in the second embodiment, via the
above-mentioned respective openings, the space S4 (see FIG. 1), the
space S3, the space S2, the space S1 and the external space are
connected to each other.
[0073] In the second embodiment having the above-mentioned
configuration, at the time of the driving of the speaker device
100, the voice coil bobbin 7 moves in the direction of the arrow Y1
and in the direction of an arrow Y5 opposite to the arrow Y1.
[0074] When the voice coil bobbin 7 is assumed to move in the
direction of the arrow Y1, as understood with reference to FIG. 1
and FIG. 10, the part of the air existing in the space S4 flows
into the space S3, and by the amount of flowing air, the part of
the air existing in the space S3 is discharged to the space S2 via
the plural openings 11ca of the supporting cap 11, as shown in the
direction of an arrow Y7. Accordingly, by the amount of air flowing
into the space S2, the part of the air existing in the space S2 is
discharged to the space S1 via the plural openings 9da of the
diaphragm 9, as shown in the direction of the arrow Y7. Further, by
the amount of air flowing into the space S1, the part of the air
existing in the space S1 is discharged to the external space via
the plural openings 4da of the frame 4, as shown in the direction
of the arrow Y7.
[0075] On the other hand, when the voice coil bobbin 7 is assumed
to move in the direction of the arrow Y5, as understood with
reference to FIG. 1 and FIG. 10, the part of the air existing in
the space S3 is discharged to the space 34. Accordingly, by the
amount of the air discharged from the space S3, the part of the air
existing in the space S2 flows into the space S3 via the plural
openings 11ca of the supporting cap 11, as shown in the direction
of an arrow Y8. In conjunction with this, by the amount of air
discharged from the space S2, the part of the air existing in the
space S1 flows into the space S2 via the plural openings 9da of the
diaphragm 9, as shown in the direction of the arrow Y8. By the
amount of the air discharged from the space S1, the part of the air
existing in the external space flows into the space S1 via the
plural openings 4da of the frame 4.
[0076] As described above, in the speaker device 100 having no
ventilation portion, when the voice coil bobbin 7 moves in the
direction of the arrow Y5 opposite to the direction of the arrow
Y1, the pressure of the space S3 becomes high, and the voice coil
bobbin 7 is hard to move. Namely, the mechanical resistance at the
time of the movement of the voice coil bobbin 7 increases.
[0077] As for this point, in the second embodiment, since the
plural openings are provided on the supporting cap 11, the
diaphragm 9 and the frame 4, the permeability becomes preferable.
Therefore, in the speaker device 100 in the second embodiment,
particularly, even when the voice coil bobbin 7 moves in the
direction of the arrow Y5, the pressure in the space S3 never
becomes high by the above-mentioned operation. Thus, in this case,
the voice coil bobbin 7 can easily move in the direction of the
arrow Y5, and the mechanical resistance at the time of the movement
of the voice coil bobbin 7 can be decreased. Thereby, the
deterioration of the sound quality can be prevented.
[0078] In addition, in the speaker device 100, when the pressure in
the space S3 becomes high as described above, external force
corresponding to the pressure operates on each component of the
vibration system 30. Thus, in this case, the strength (bonding
strength) among the respective components of the vibration system
30 has to be reinforced. As for this point, in the second
embodiment, since the permeability is ensured, the pressure in the
space S3 does not become high, as described above. Therefore, the
strength (bonding strength) among the respective components of the
vibration system 30 does not have to be reinforced in a positive
manner. Namely, in the second embodiment, since the ventilation
portion is provided, the strength (bonding strength) among the
respective components of the vibration system 30 becomes high at
the time of the driving of the speaker device 100 in comparison
with the speaker device having no ventilation portion. This is the
reinforcement effect. Thereby, it becomes possible to operate the
vibration system 30 with appropriate softness. As a result, the
vibration system 30 can be precisely controlled, and the speaker
device 100 can be easily in a still state. Namely, the damping
effect can be improved.
[Modification]
[0079] In the present invention, the mounting structure (bonding
manner) at the cap 12 and the outer peripheral edge portion of the
diaphragm 9 is not limited to the above-mentioned structure, and
other various manners can be employed FIG. 7 shows an example of
the bonding methods. FIG. 7 is a partly cross-sectional view
corresponding to a broken line area E11 shown in FIG. 5.
[0080] As shown in FIG. 7, in this example, the bonding manner of
the outer peripheral edge portion of the cap 12 and the diaphragm 9
is different from the above-mentioned embodiments. Namely, in this
example, as shown in the broken line area E12 in FIG. 7, the second
flat portion 9b and the projecting portion 9ba are not provided in
the vicinity of the outer peripheral edge portion of the diaphragm
9. Instead, the portion of the diaphragm 9 corresponding to the
broken line area E12 and the outer peripheral edge portion of the
cap 12 structurally contact. In this example, the outer peripheral
edge portion of the cap 12 and the diaphragm 9 at the correspondent
position are fixed via the adhesive (not shown). By such a
structure, the operation and effect of the present invention can be
also obtained.
[0081] In addition, in the above-mentioned second embodiment, as
the ventilation portions, the plural openings 11ca are provided on
the side wall 11c of the supporting cap 11. However, this invention
is not limited to this. As shown in FIG. 11A, the portions
corresponding to the plural openings 11ca on the side wall 11c of
the supporting cap 11 may be constructed by a member having the
permeability, e.g., a material such as a fabric on which large
meshes are formed. Instead, as shown in FIGS. 11D and 11C, the
entire side wall 11c or the entire supporting cap 11 may be
constructed by a member having the permeability, e.g., a material
such as a fabric on which large meshes are formed. Thereby, since
the member having the permeability functions as the ventilation
portion, the operation and effect similar to those in the second
embodiment can be obtained.
[0082] The invention may be embodied on other specific forms
without departing from the spirit or essential characteristics
thereof. The present embodiments therefore to be considered in all
respects as illustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather than by the
foregoing description and all changes which come within the meaning
an range of equivalency of the claims are therefore intended to
embraced therein.
[0083] The entire disclosure of Japanese Patent Applications No.
2004-309329 filed on Oct. 25, 2004 and No. 2004-374313 filed on
Dec. 24, 2004 including the specifications, claims, drawings and
summaries are incorporated herein by reference in their
entirety.
* * * * *